The present invention relates to a hydrogen generating apparatus and, more particularly, to a hydrogen generating apparatus which is suitable for use as an on-site type hydrogen generating system, an industrial fuel battery system and so forth.
In general, a hydrogen generating apparatus has, in order to generate a hydrogen rich gas through a steam-reforming of a material such as hydrocarbon (CH.sub.4) or alcohol, a reformer and a CO converter (referred to as "shift converter", hereinafter) which respectively incorporate catalysts. Usually, a desulfurization reactor is provided in a material gas supplying system of the apparatus.
The reforming reaction is expressed by the following formula: EQU CH.sub.4 +2H.sub.2 O.fwdarw.4H.sub.2 +CO.sub.2
wherein the reaction in the reformer and the reaction in the shift converter are respectively expressed by the following formulae (1) and (2). EQU CH.sub.4 +H.sub.2 O.fwdarw.CO+3H.sub.2 ( 1) EQU CO+H.sub.2 O.fwdarw.H.sub.2 +CO.sub.2 ( 2)
In the conventional hydrogen generating apparatus, an inert gas heated in a reformer is made to flow through a process flow path so as to raise temperatures of the shift converter and the heat exchangers which are downstream from the reformer. On the other hand, the desulfurization reactor, which is disposed upstream of the reformer, is heated by a heater.
This type of hydrogen generating apparatus is shown in, for example, "Future Prospect of Phosphate-type Fuel Battery Power Generating Technique, Report No. 2", Agency of Industrial Science and Technology, Ministry of International Trade and Industry, page 4.2-5 to 4.2-7, January 1986.
In the known technique described above, no specific consideration is given to the time for heating up the shift converter. The time required for heating the shift converter to a temperature for activating the catalyst is a very important factor which rules the start-up time of the reforming system. Hitherto, a considerably long time is required for starting up the reforming system.